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Author Topic: Tire sizing  (Read 1438 times)

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Offline Wesley

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Tire sizing
« on: March 03, 2017, 09:19:46 AM »
Educate me on tire sizing and determining fit.

I just purchased a 2014 Chrysler Town and Country van.  Stock tire size is 225/65/r17.  On hand from a different vehicle I have winter tires that are 235/65/r17.  Is it possible to fit the 235/65/r17 winter tires on the van? 

Using tire size calculators, I understand that 235/65/r17 tires would increase in both height (increase of 0.5" or +1.8%) and width (increase of 0.4" or +4.5%).  But, is there an quick/easy way to determine if they'd fit without mounting them and physically installing them to check for rubbing against fender wells and suspension parts?  I'd rather not pay to mount/balance them only to find out they wouldn't fit.

Basically, I'm trying to see if I can use what I already have on hand.  If it wouldn't work, I can purchase winter tires for it next year in the stock 225/65/r17 size.  I thought I'd see if the collective had any input or experience with this.  Thanks in advance. 

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Re: Tire sizing
« Reply #1 on: March 03, 2017, 09:53:45 AM »
Go to tirerack.com
Put in your van and it will tell you what size tires can be fitted
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Online bedlamite

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Re: Tire sizing
« Reply #2 on: March 03, 2017, 10:12:12 AM »
Tirerack is great, but will generally only tell you the official manufacturer recommended size. Usually you can fit tires that are 10-20mm wider, but you may have to drop the aspect ratio from 65 to 60 to do it. The only way to know for sure is to try it.
A plan is just a list of things that doesn't happen.

Offline Max Wedge

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Re: Tire sizing
« Reply #3 on: March 03, 2017, 10:32:38 AM »
Your increase is only half of the diameter of the increase. (The radius). Plus there are build variances the manufacturer allow for, including tire 'growth' at speed. Another thing they allow for is the use of tire chains. If you are never going to run them, no worries. At the very worst, you might get a touch when turned to the extreme and at full compression or extension, like when backing out of a driveway.

My $0.02 is: No worries, I would do it in a second, and not even think twice.
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Online Patmo

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Re: Tire sizing
« Reply #4 on: March 03, 2017, 10:40:42 AM »
IF you have access to a jack and jackstands, its not very difficult to check.  Can also be done on a lift.

1st.....get the vehicle up in the air
2nd....turn the front wheels to full lock each way and measure the distance between the tire and any bodywork at its CLOSEST point
3rd....check, with the wheels straight ahead, the clearance between the inside of the tire and any suspension parts
4th....put the vehicle back down on the ground, so that the weight of the vehicle is on the tires, and recheck the clearance the same way...lock to lock and inside of tire to suspension parts.  Pay attention to clearance around the front wheel openings as well.

Having said all this, keep in mind that the OVERALL height and width will increase the amount you said, but the INSIDE width and UPPER height will only increase 1/2 of that amount......the other 1/2 is UNDER the vehicle or OUTSIDE the center line.  What that means is that the larger tires really only effect the inside/upper dimensions by about 1/4 of an inch.  Your new tires start with an average of 10/32 of tread and are considered worn out at 2/32 of tread in all states but California. That is a difference of 8/32 on top and 8/32 on the bottom.  Together that makes 16/32 or 1/2 of an inch.  You can expect the overall height of a tire to drop by 1/2 of an inch during its lifetime.  (helpful to remember this when you get new tires and suddenly your speedometer isn't accurate)

Bottom line......going from a 225/65 to a 235/65 wouldn't concern me in the least.      BUT makes sure that ALL the tires are the same size on each axle, otherwise you can have problems with pulling or even mess up the anti-lock brakes or drivetrain. 

Online CLAY

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Re: Tire sizing
« Reply #5 on: March 03, 2017, 05:45:31 PM »
IF you have access to a jack and jackstands, its not very difficult to check.  Can also be done on a lift.

1st.....get the vehicle up in the air
2nd....turn the front wheels to full lock each way and measure the distance between the tire and any bodywork at its CLOSEST point
3rd....check, with the wheels straight ahead, the clearance between the inside of the tire and any suspension parts
4th....put the vehicle back down on the ground, so that the weight of the vehicle is on the tires, and recheck the clearance the same way...lock to lock and inside of tire to suspension parts.  Pay attention to clearance around the front wheel openings as well.

Having said all this, keep in mind that the OVERALL height and width will increase the amount you said, but the INSIDE width and UPPER height will only increase 1/2 of that amount......the other 1/2 is UNDER the vehicle or OUTSIDE the center line.  What that means is that the larger tires really only effect the inside/upper dimensions by about 1/4 of an inch.  Your new tires start with an average of 10/32 of tread and are considered worn out at 2/32 of tread in all states but California. That is a difference of 8/32 on top and 8/32 on the bottom.  Together that makes 16/32 or 1/2 of an inch.  You can expect the overall height of a tire to drop by 1/2 of an inch during its lifetime.  (helpful to remember this when you get new tires and suddenly your speedometer isn't accurate)

Bottom line......going from a 225/65 to a 235/65 wouldn't concern me in the least.      BUT makes sure that ALL the tires are the same size on each axle, otherwise you can have problems with pulling or even mess up the anti-lock brakes or drivetrain.

What he said.  Run 'em.
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Offline kneescrubber

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Re: Tire sizing
« Reply #6 on: March 03, 2017, 07:54:50 PM »
In 1973 I bought a 1965 Impala SS. I put Mickey Thompson L60's in back and J60's in front using ET 5 spoke mags. It looked bitchin'. But I had to install Gabriel air shocks in back because the tires didn't fit inside the wheel wells.

There's ALWAYS a work around.

 :shrug:
Do not go where the path may lead, go instead where there is no path and leave a trail.

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Offline Wesley

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Re: Tire sizing
« Reply #7 on: March 06, 2017, 09:10:32 AM »
Tirerack is great, but will generally only tell you the official manufacturer recommended size.

That is what I had noticed as well.

Offline Wesley

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Re: Tire sizing
« Reply #8 on: March 06, 2017, 09:20:51 AM »
Thanks for the replies, everyone.  When the weather warms up I'll check for any clearance issues as advised.

Follow up question:  The 235/65/r17 tires come off a 17" x 7" wheel.  Van specs show it has a 17" x 6.5" wheel.  Are 235/65/r17 tires still mountable if the rim width is narrower (i.e. when mounting tires, is only diameter of the rim important, going from one 17" rim to another 17" rim and rim width doesn't factor in, or does it)?

Offline Wesley

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Re: Tire sizing
« Reply #9 on: March 06, 2017, 09:24:34 AM »
In 1973 I bought a 1965 Impala SS....
 :shrug:

Dating yourself, aren't you?   :)  That may or may not have been well before I was born.  Yet, I am happy to rely on and learn from your life experiences, so thank you for that.

Online Jim

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Re: Tire sizing
« Reply #10 on: March 06, 2017, 09:43:13 AM »
What he said.  Run 'em.

Yea - run'm.  Pay attention at initial turning for rub (full lock - bumping up a driveway incline - compressing one of the turning wheels).

I have what seems similar - just slightly taller tires on my car - with a goal to bring highway RPM's down a bit. RPM's went down (at 75MPH) about 250RPM and MPH went up about 1.5 to 2.5 MPH. I notice no rubbing.
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Offline Max Wedge

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Re: Tire sizing
« Reply #11 on: March 06, 2017, 11:05:05 AM »
In 1973 I bought a 1965 Impala SS....
 :shrug:

Dating yourself, aren't you?   :)  That may or may not have been well before I was born.  Yet, I am happy to rely on and learn from your life experiences, so thank you for that.

What is really dating is the letter sizing of the tires, which went away a little while after the time radial tires were introduced.
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Offline kneescrubber

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Re: Tire sizing
« Reply #12 on: March 06, 2017, 12:27:20 PM »
In 1973 I bought a 1965 Impala SS....
 :shrug:

Dating yourself, aren't you?   :)  That may or may not have been well before I was born.  Yet, I am happy to rely on and learn from your life experiences, so thank you for that.

What is really dating is the letter sizing of the tires, which went away a little while after the time radial tires were introduced.

 :lol:

True dat!
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Online bedlamite

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Re: Tire sizing
« Reply #13 on: March 06, 2017, 11:56:53 PM »
What is really dating is the letter sizing of the tires, which went away a little while after the time radial tires were introduced.

Many years ago I had some L60-15 BFG All Terrain T/A on the back of my Baja Bug.
A plan is just a list of things that doesn't happen.

Offline Max Wedge

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Re: Tire sizing
« Reply #14 on: March 07, 2017, 05:29:42 AM »
What is really dating is the letter sizing of the tires, which went away a little while after the time radial tires were introduced.

Many years ago I had some L60-15 BFG All Terrain T/A on the back of my Baja Bug.

I had some on my very first Power Wagon.
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